This project investigates the relationship between migraine headache and pregnancy based on the data collected from a large group of women in pregnancy the Collaborative Perinatal Project gravidae. Subgroups of pregnant women characterized by the absence and presence of migraine and other recurrent headaches prior to or during pregnency, are identified. Characteristics of these subgroups are investigated on a variety of demographic, sociological, medical and obstetric factors, and the association of headache with other disorders. Seven data files were created bearing information of migraine history, use of headache medications, and frequencies of headache during pregnancy. Preliminary results showed pregnant women with a migraine history had more other symptoms and illnesses during their pregnancies than women without a migraine history. Children of mothers with a history of migraines appear to have higher incidence of seizures than children born to mothers in the non-migraine group. More careful statistical analyses will be carried out.